Lubricants have traditionally been manufactured using petroleum as a base. Unfortunately, petroleum usage has been linked to various problems. First, petroleum supply is finite, and petroleum supplies continue to be depleted through numerous demand sources, including petroleum uses in gasoline, plastics, cosmetics, oils, and lubricants, to name just a few. Moreover, petroleum processing has a large environmental footprint, including the release of greenhouse gasses and other pollutants. For example, petroleum-based lubricants are highly toxic. Accordingly, they can cause extreme damage to the environment, and wild life in particular, if spilled during transportation or use, not disposed of properly, or otherwise discharged into the environment. In response to these problems, researchers have searched for alternative sustainable lubricant base sources.
Plants have been used as one family of alternative lubricant base sources. Many different plant-based oils may be processed to form so-called bio-lubricants. For example, various types of vegetable oils have been used as a base for bio-lubricants. However, the use of vegetable oils to produce bio-lubricants also poses problems. For example, vegetable oils, and the plants used to yield vegetable oils, have other uses—particularly as a food source. In addition, although vegetable oils make excellent lubricants due to their polar functionality, high viscosity, and high flash points, they are limited by poor thermal and oxidative stability. Accordingly, they typically require additives and chemical modifications prior to incorporation into commercial lubricants. Accordingly, the cost of using vegetable oils as lubricants tends to be relatively high as compared to the use of petroleum, and wide-scale use of vegetable oils would raise demand for the corresponding plant materials and would raise the cost of the corresponding food-products produced from the same base plants.
As a solution, some researchers have attempted to produce lubricants from algal oils. Algae is traditionally not used as a food source, and tends to be relatively easy to grow. Indeed, systems and methods for efficiently growing algae using recycled flue gas have been previously disclosed. However, using algae to produce algal oils suitable for use in bio-lubricants still poses challenges. First, algal oil yield from algae grow plants has traditionally been insufficient to make algal oil based bio-lubricant production economically feasible. Second, algal oil profiles tend to be inadequate to produce a stable bio-lubricant. In particular, vegetable oils with high oleic acid contents provide improved thermal and oxidative stability, but currently available algal oils do not have sufficient levels of oleic acid, and thus suffer thermal and oxidative instability. Together, these factors have made current attempts at producing algal oil based bio-lubricants too costly to be commercially viable.